This invention relates to an endoscopic treatment tool which is adapted to pass through a forceps channel of an endoscope for medical or surgical treatment.
In general, an endoscopic treatment tool such as a high-frequency snare, grip forceps, or biopsy forceps is operated such that a driven part at a distal end of a flexible sheath passing through a forceps channel is remote-controlled with an operation part provided at a proximal, operator-side end via an operation wire inserted into the sheath.
However, if the driven part is not directed to a diseased part, it is difficult to apply the treatment to the diseased part as intended. To overcome this problem, Japanese Utility Model Kokoku Publication No. Sho-61-18885 proposes a structure wherein the operation wire is arranged rotatable relative to the sheath to thereby make it possible to rotate the distal end driven part. Further, Japanese Utility Model Kokoku Publication No. Sho-52-40616 proposes a structure wherein a rotating-mechanism is incorporated to the distal end part of the sheath to thereby make it possible to control the rotative direction of the distal end driven part through a second discrete operation wire.
These proposed structures still have the following deficiencies:
In the former case, if a soft stranded wire constructed by many element wires is used as the operation wire, the rotational is not sufficiently transmitted to the distal end driven part since the operation wire dampens or absorbs the rotation. On the other hand, the use of a hard stranded wire constructed by a small number of element wires, or a single wire as the operation wire will result in improper transmission of the rotation since that wire is likely to be bent permanently (poor in flexibility).
In the latter case, the distal end driven part, in fact, cannot be rotated substantially as intended since the rotating mechanism must be added to a part where a extremely precision mechanism need inherently occupy.